PCI: Fix code formatting inconsistencies

Remove unnecessary "return;" in void functions and format consistently.
No functional change intended.

Link: https://lore.kernel.org/r/20230824193712.542167-12-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>